Prior art methods and apparatus for polishing a semiconductor wafer are shown by U.S. Pat. Nos. 3,439,371; 3,979,239; 4,193,226; 4,907,931; 4,910,155; 4,934,102; 4,944,119; 5,095,661; 5,144,711 and 5,403,228.
Improvements for prior art componentary used in the aforesaid are shown in U.S. Pat. Nos. 5,032,203; 5,036,630; 5,081,051; 5,177,908; 5,423,558 and 5,663,637.
With the exception of U.S. Pat. No. 4,934,102 assigned to the common assignee hereof and U.S. Pat. No. 3,439,371 the prior art apparatus and componentary deal with the use of flat pads in the polishing apparatus that are rotating under or over or a semiconductor wafer that may be itself rotating in a stationary plane or oscillating while rotating in a stationary plane to ensure full surface treatment.
As for U.S. Pat. Nos. 4,934,102 and 3,439,371 a roller, rather than a pad is employed and rotated perpendicularly to the plane of rotation for the wafer to polish one side of the semiconductor wafer.
It is in the improvement of this type of polishing apparatus that this invention is directed. More particularly, these current polishing apparatus have (1) leading edge and trailing edge slurry delivery problems resulting in non uniform fresh slurry contact over the entire wafer surface; (2) problems of wafer scratching due to slurry and etch residual agglomerations becoming embedded in the polish pad, traveling with the pad and scratching wafers; and (3) the problem of newer larger wafers increasing tool and pad size with doubtful uniform results.